Remove more bits of Python < 3.8 support

fixtures/tests/_fixtures/test_popen.py

@@ -80,9 +80,8 @@ def test_handles_all_Popen_args(self):
             pass_fds="pass_fds",
             encoding="encoding",
             errors="errors",
+            text="text",
         )
-        if sys.version_info >= (3, 7):
-            all_args["text"] = "text"
         if sys.version_info >= (3, 9):
             all_args["group"] = "group"
             all_args["extra_groups"] = "extra_groups"
@@ -100,16 +99,6 @@ def get_info(proc_args):
         fixture = self.useFixture(FakePopen(get_info))
         fixture(**all_args)
 
-    @testtools.skipUnless(
-        sys.version_info < (3, 7), "only relevant on Python <3.7"
-    )
-    def test_rejects_3_7_args_on_older_versions(self):
-        fixture = self.useFixture(FakePopen(lambda proc_args: {}))
-        with testtools.ExpectedException(
-            TypeError, r".* got an unexpected keyword argument 'text'"
-        ):
-            fixture(args="args", text=True)
-
     @testtools.skipUnless(
         sys.version_info < (3, 9), "only relevant on Python <3.9"
     )
@@ -175,9 +164,6 @@ def test_function_signature(self):
             fake_kwargs.remove('user')
             fake_kwargs.remove('umask')
 
-        if sys.version_info < (3, 7):
-            fake_kwargs.remove('text')
-
         self.assertSetEqual(
             fake_kwargs,
             real_kwargs,

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py37,py38,py39,py310,py311,py312,pypy3
+envlist = py38,py39,py310,py311,py312,pypy3
 minversion = 3.1
 
 [testenv]